Detection of bovine papillomavirus type 1 genomes and viral gene expression in equine inflammatory skin conditions.

This study investigates the occurrence of bovine papillomavirus type 1 (BPV-1) in horses and its possible link to equine skin inflammation. It concludes that some cases of equine dermatitis are associated with the presence of circular, episomally maintained BPV-1 genomes that express viral transcripts.

Research Overview

• Generally, papillomaviruses are species-specific, with limited evidence of cross-species infection. An exception involves BPV-1/BPV-2, observed to infect horses and cause a type of skin tumour known as equine sarcoids.
• The study focuses on the evidence of BPV-1 in equine inflammatory skin conditions, extending beyond the previously documented non-sarcoid equine tumours and equine papillomas.

Findings

• The researchers found evidence of episomal circular double-stranded BPV-1 genomes within equine inflammatory skin conditions. Episomal genomes are pieces of viral DNA that exist independently from the host’s chromosomal DNA.
• The amount of BPV-1 present varied between 0.2 and 155 copies per cell.

Viral Gene Expression

• The study noted the expression of three BPV-1 genes (E1, E2, E5) in these conditions, suggesting an active infection.
• These three genes are part of BPV-1’s genome and play vital roles in the virus’s life cycle, which includes replicating its own DNA and ability to stimulate cell proliferation in the host.

Conclusions

• The presence of the circular, episomally maintained BPV-1 genomes and the expression of BPV-1 genes indicate that this specific virus may play a role in some cases of equine dermatitis.
• The research thus extends the known instances of cross-species infection with BPV beyond equine sarcoids.